Integrated sensor based on photon lead and preparation method thereof

Abstract

The invention provides an integrated sensor based on a photon lead and a preparation method thereof, the integrated sensor based on the photon lead comprises a wafer, a sensing unit, an optical fiber unit and the photon lead, the sensing unit is arranged at the top of the wafer, the sensing unit is also bonded to the optical fiber unit, and the optical fiber unit is arranged on the wafer. The optical fiber unit is connected with the sensing unit through the photon lead, the wafer is used for supporting the sensing unit, the sensing unit is used for modulating an optical signal, the optical fiber unit is used for inputting the optical signal output by the excitation light source into the photon lead and receiving a returned modulation signal of the sensing unit, and the photon lead is used for inputting and outputting the optical signal. According to the invention, the sensing unit and the optical fiber unit are connected through the photon lead, the mode field mismatch loss is reduced, the stability of the sensor in an extreme environment is improved, the long-term reliable and stable operation of the sensor is ensured, the packaging cost is reduced, and the application of a miniaturized sensor is promoted.

Description

Technical Field

[0001] The present disclosure relates to the field of semiconductor technology, and in particular to an integrated sensor based on photonic leads and a method for preparing the same. Background Art

[0002] Integrated optical sensors, as core components for information perception, play an irreplaceable role in communications, biomedicine, industrial monitoring, quantum computing, and intelligent sensing. Their performance directly impacts system accuracy, stability, and integration. Traditional optical sensor packaging and connection technologies rely on mechanical alignment and gluing processes, which present bottlenecks such as high loss, poor stability, and large size. These issues are particularly prone to signal distortion in complex environments, such as those affected by vibration, temperature fluctuations, and electromagnetic interference. This severely restricts the large-scale application of high-precision sensing systems.

[0003] A search of existing technologies revealed that Nicole Lindenmann et al. from the Karlsruhe Institute of Technology published an article titled "Connecting Silicon Photonic Circuits to Multicore Fibers by Photonic Wire Bonding" in the Journal of Lightwave Technology, 2015. In the article, they proposed and verified photonic wire bonding (PWB) technology, which uses three-dimensional laser direct writing to create free-form polymer waveguides to achieve efficient coupling between multi-core optical fibers and silicon photonic chips. Experiments have shown that this technology eliminates the need for active alignment and can automatically compensate for positional deviations in the optical fiber cores, with coupling loss as low as 1.7 dB. However, due to the susceptibility of the material to shrinkage and deformation during the two-photon polymerization direct writing process, some PWBs exhibit abnormally high losses, resulting in poor device performance consistency. Furthermore, the reliance on precise point-by-point direct writing technology results in a single PWB processing time of several minutes to several hours. The current production speed is difficult to meet the needs of large-scale mass production, which seriously restricts the practical application of this technology.

[0004] Qian Wang et al. from the Institute of Microelectronics, Chinese Academy of Sciences, published an article titled "Design of ultrahigh-Q silicon microring resonators based on free-form curves" in Optics Express, 2024. They proposed a novel design method for silicon microring resonators based on Bessel free-form curves, realizing ultra-compact and ultra-high Q devices. The curved waveguide adopts gradient width and curvature, which effectively suppresses the excitation of high-order modes and reduces mode mismatch losses. The effective bending radius of the ring resonator is only 20μm, making the device structure extremely compact and flexible. It shows an ultra-high load Q value of 1.86×10^6 and a waveguide loss of only 0.24dB / cm. However, the use of narrow waveguides will increase the coupling loss between the fundamental mode and the high-order mode, which will affect the quality factor of the device. At the same time, it uses traditional end-face coupling, and the device has large coupling loss and is easily affected by external interference.

[0005] In summary, the packaging and interconnection of traditional optical sensors mainly rely on mechanical calibration and adhesive fixation, facing inherent defects such as large insertion loss, insufficient long-term stability and bloated device size. Under harsh operating conditions such as dynamic mechanical vibration, temperature fluctuations and strong electromagnetic fields, their optical paths are prone to deviation or degradation, causing signal attenuation and noise interference, which has become a core obstacle to the large-scale deployment of high-precision sensor networks.

[0006] Integrated optical sensors based on photonic lead technology break through the above limitations through innovative structural design. Photonic leads use a two-photon direct writing process to directly construct a three-dimensional tapered waveguide between the optical fiber and the chip grating coupler, achieving ultra-low loss transmission of optical signals and precise mode field matching. Compared with traditional packaging technology, photonic lead technology has the following significant advantages: First, through nanometer-level positioning accuracy and gradient refractive index design, it eliminates interface reflections and modal mismatches, thereby improving the signal-to-noise ratio of the sensing signal; second, it adopts a hybrid structure of flexible polymers and inorganic composite materials, which has both mechanical flexibility and environmental tolerance, and is suitable for long-term stable operation in extreme environments; third, photonic leads are compatible with CMOS processes, support large-scale wafer-level manufacturing, significantly reduce packaging costs and promote sensor miniaturization.

[0007] Currently, this technology is showing potential in biological monitoring, such as implantable pH / temperature sensors; industrial equipment status sensing, such as strain detection in high-temperature and high-pressure environments; and autonomous driving LiDAR systems. Through the efficient optical interconnection capabilities of photonic wiring technology, optical sensors can be seamlessly integrated with on-chip light sources, detectors, and signal processing units to build an all-optical intelligent sensing network. This provides a technological foundation for the development of next-generation high-precision, highly reliable, and multimodal sensing systems, fueling the leapfrog development of the Internet of Things, smart healthcare, and Industry 4.0.

[0008] Photonic Wiring (PWB) technology achieves ultra-low-loss, high-precision optical interconnection through three-dimensional waveguide direct writing, combining environmental tolerance with CMOS compatibility, and provides an innovative solution for integrated optical sensors. Therefore, it is urgent to develop a new optical sensor connection and coupling technology that optimizes materials and processes, breaks through the bottlenecks of accuracy, efficiency, and reliability, and promotes the practical application of highly integrated sensing systems. Summary of the Invention

[0009] In view of the defects in the prior art, the present invention aims to provide an integrated sensor based on photonic leads and a method for preparing the same.

[0010] In a first aspect, the present application provides an integrated sensor based on photonic leads, comprising:

[0011] A wafer, a sensing unit, an optical fiber unit, and a photon lead. The sensing unit is arranged on top of the wafer, and the sensing unit is also bonded to the optical fiber unit. The optical fiber unit is connected to the sensing unit through the photon lead. The wafer is used to support the sensing unit. The sensing unit is used to modulate the optical signal. The optical fiber unit is used to input the optical signal output by the excitation light source into the photon lead and receive the modulated signal of the sensing unit transmitted back. The photon lead is used for input and output of the optical signal.

[0012] Optionally, a protective layer is further included, wherein the protective layer is arranged on the surface of the integrated sensor based on the photon lead, and the protective layer is used to protect the integrated sensor based on the photon lead.

[0013] Optionally, the sensing unit includes a waveguide layer and a functional layer, the waveguide layer adopts an optical resonant cavity structure, the optical resonant cavity structure adopts any one or more combinations of a microring resonant cavity, a nanobeam resonant cavity, a multi-ring resonator array, a Fabry-Perot resonant cavity, a whispering gallery mode resonant cavity or a photonic crystal resonant cavity, the material of the waveguide layer adopts any one or more combinations of silicon, silicon nitride, lithium niobate thin film, indium phosphide or gallium arsenide, the waveguide layer is used as an optical transmission channel, and the functional layer is used to perform preset functional detection on the detection target.

[0014] Optionally, the optical fiber unit adopts any one of single-mode optical fiber, multi-mode optical fiber and D-type optical fiber, and the material of the optical fiber unit adopts any one of adaptive optical fiber, plastic optical fiber and glass optical fiber.

[0015] Optionally, a grating coupler is further included, which is arranged at both ends of the waveguide layer of the sensing unit, and is connected to the optical fiber unit through the photon lead. The grating coupler is used for input of optical signals and waveguide output.

[0016] Optionally, the photon lead adopts a three-dimensional tapered transition structure, the cross-sectional diameter of the input end of the photon lead matches the cross-sectional diameter of the core of the optical fiber unit, the cross-sectional diameter of the output end of the photon lead matches the waveguide width of the grating coupler, and the material of the photon lead adopts any one or more combinations of ultraviolet-curable photosensitive polymers and organic-inorganic hybrid materials.

[0017] Optionally, the wafer is made of any one or more combinations of silicon-on-insulator (SOI), silicon wafer, sapphire, and quartz, and the wafer is used as a substrate for the integrated sensor based on photonic leads.

[0018] Optionally, the protective layer is made of an inorganic-flexible composite material.

[0019] In a second aspect of the present application, a method for preparing an integrated sensor based on photonic leads is provided, comprising:

[0020] Spin-coating a photoresist on a predetermined wafer, and performing grating patterning on the wafer on which the photoresist is spun, to determine the patterned photoresist;

[0021] Etching the non-photoresist area on the wafer using a plasma dry etching process to generate a sensing unit and a grating coupler;

[0022] Using a femtosecond laser to scan a photosensitive polymer to generate a photonic lead connecting a preset optical fiber unit and the grating coupler;

[0023] A protective layer is deposited on the surfaces of the wafer, the sensing unit, the grating coupler, the preset optical fiber unit, and the photon lead to determine an integrated sensor based on the photon lead.

[0024] Optionally, the material of the protective layer is any one or more combinations of silicon oxide, silicon nitride and polyimide.

[0025] Compared with the prior art, the embodiments of the present disclosure have at least one of the following beneficial effects:

[0026] The present application discloses an integrated sensor based on photonic leads, which uses photonic leads to form a tapered waveguide to connect the optical fiber unit and the sensing unit, thereby realizing mode field matching coupling between the optical fiber unit and the sensing unit, and is used for the input and output of optical signals, thereby reducing mode field mismatch loss, improving the stability of the sensor in extreme environments, and ensuring long-term reliable and stable operation of the sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Other features, objects and advantages of the present disclosure will become more apparent upon reading the detailed description of non-limiting embodiments with reference to the following drawings:

[0028] Figure 1 The figure is a schematic diagram of the overall structure of an integrated sensor based on photon leads according to an exemplary embodiment.

[0029] Figure 2 The figure is a schematic diagram of the overall structure of an integrated optical humidity sensor based on photon leads according to an exemplary embodiment.

[0030] Figure 3 The figure is a flow chart of a method for preparing an integrated sensor based on photonic leads according to an exemplary embodiment.

[0031] Figure 4 The figure is a schematic diagram showing the preparation of an integrated optical temperature sensor based on photonic leads according to an exemplary embodiment.

[0032] Figure 5 The figure is a schematic diagram showing the preparation of a sensing unit according to an exemplary embodiment.

[0033] In the figure, 1 is a wafer, 2 is an optical fiber unit, 21 is a core layer of the optical fiber unit, 22 is a cladding layer of the optical fiber unit, 3 is a grating coupler, 4 is a sensing unit, 41 is a waveguide layer, 5 is a photon lead, 6 is a photoresist, 7 is silicon dioxide, and 8 is a silicon layer. DETAILED DESCRIPTION

[0034] The present disclosure is described in detail below with reference to specific embodiments. The following embodiments will help those skilled in the art further understand the present disclosure, but are not intended to limit the present disclosure in any way. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the scope of the present disclosure. These modifications and improvements are all within the scope of protection of the present disclosure.

[0035] In the description of the embodiments of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "bottom", "inside", "outside", "clockwise", "counterclockwise", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0036] In the description of the embodiments of the present application, the meaning of "multiple" is two or more, unless otherwise clearly specified and specifically defined. In the present application, unless otherwise clearly specified and defined, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be a communication between the internal parts of two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0037] In the embodiments of the present application, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to the process, method, product, or apparatus.

[0038] Existing optical sensors suffer from high losses, poor long-term stability, and bulky components. They are also prone to signal distortion in extreme environments, hindering the large-scale application of high-precision sensing systems. To address these issues, this application proposes an integrated sensor based on photonic leads and a method for fabricating it to address these issues.

[0039] Figure 1 The figure is a schematic diagram of the overall structure of an integrated sensor based on photon leads according to an exemplary embodiment.

[0040] Reference Figure 1 As shown, an embodiment of the present application provides an integrated sensor based on photon leads, including: a wafer 1, a sensing unit 4, an optical fiber unit 2, and a photon lead 5.

[0041] Specifically, the sensing unit 4 is disposed on the top of the wafer 1 , and the sensing unit 4 is also bonded to the optical fiber unit 2 . The optical fiber unit 2 is connected to the sensing unit 4 via a photon lead 5 . The wafer 1 is used to support the sensing unit 4 .

[0042] The sensing unit 4 may be bonded to the tip or side wall of the optical fiber unit 2 .

[0043] The sensing unit 4 is used to modulate the optical signal, the optical fiber unit 2 is used to input the optical signal output by the excitation light source into the photon lead 5 and receive the modulated signal transmitted back from the sensing unit 4, and the photon lead 5 is used for input and output of the optical signal.

[0044] In the above-mentioned embodiment of the present application, a photon lead 5 is used to form a tapered waveguide to connect the optical fiber unit 2 and the sensor unit 4, thereby realizing mode field matching coupling between the optical fiber unit 2 and the sensor unit 4, which is used for the input and output of optical signals, reduces mode field mismatch loss, improves the stability of the sensor in extreme environments, and ensures long-term reliable and stable operation of the sensor; moreover, the photon lead 5 is compatible with CMOS technology, supports wafer-level integration, reduces packaging costs and promotes the application of miniaturized sensors; the photon lead 5 can also be compatible with single-mode / multi-mode optical fibers, a variety of waveguide materials and functional coatings through a flexible combination of materials and structures, and is suitable for diverse scenarios such as biological implant monitoring, industrial equipment status perception and autonomous driving lidar, providing an all-optical interconnection foundation for intelligent sensor networks.

[0045] Reference Figure 1 As shown, in some specific embodiments, the material of the wafer 1 is any one or more combinations of silicon-on-insulator wafer, silicon wafer, sapphire and quartz, and the wafer 1 is used as a substrate for an integrated sensor based on the photonic lead 5 .

[0046] Specifically, the wafer 1 serves as a substrate for the photonic wire-based integrated sensor and as a supporting base for the entire photonic wire-based integrated sensor, providing mechanical stability and optical support for the photonic wire-based integrated sensor.

[0047] In some specific embodiments, the sensing unit 4 includes a waveguide layer 41 and a functional layer.

[0048] Specifically, the waveguide layer 41 adopts an optical resonant cavity structure, which adopts any one or more combinations of a microring resonant cavity, a nanobeam resonant cavity, a multi-ring resonator array, a Fabry-Perot resonant cavity, a whispering gallery mode resonant cavity or a photonic crystal resonant cavity.

[0049] The waveguide layer of the sensing unit 4 may adopt an optical resonant cavity structure manufactured using MEMS processing technology. The adopted optical resonant cavity structure includes but is not limited to the various structures mentioned above.

[0050] In this embodiment, the waveguide layer of the sensing unit 41 adopts a micro-ring resonant cavity.

[0051] The material of the waveguide layer is any one or more combinations of silicon, silicon nitride, lithium niobate film, indium phosphide or gallium arsenide.

[0052] The materials of the waveguide layer of the sensing unit 4 include but are not limited to the aforementioned materials.

[0053] The waveguide layer is used as a light transmission channel.

[0054] The refractive index of the waveguide layer ranges from 1.8 to 3.5, and the thickness of the waveguide layer ranges from 100 to 3000 nm, forming a light transmission channel with lower loss.

[0055] In some specific embodiments, the functional layer of the sensing unit 4 is used to perform preset functional detection on the detection target.

[0056] Specifically, the preset functions may include temperature, humidity, and pressure detection. Thus, the functional layer of the sensing unit 4 can perform temperature, humidity, and pressure detection on the detection target. The functional layer of the sensing unit 4 is designed with differentiated materials and micro-nanostructures based on the detection requirements of the detection target.

[0057] For example, the functional layer of the sensing unit 4 may use doped silicon dioxide or silicon nitride film as a temperature sensitive medium, and achieve high-sensitivity temperature response by adjusting the thermo-optic coefficient to perform temperature detection.

[0058] For example, the functional layer of the sensing unit 4 may use polyvinyl alcohol or polyimide material as the humidity sensitive medium, and the humidity detection is performed by adjusting the water absorption and expansion characteristics of the humidity sensitive medium by modulating the effective refractive index of the waveguide layer.

[0059] Exemplarily, the functional layer of the sensing unit 4 can be made of polydimethylsiloxane or hydrogel, and a periodic air hole or periodic dielectric column array can be designed. The periodic air hole or periodic dielectric column array can realize deformation transmission under small pressure at a low elastic modulus to perform pressure detection.

[0060] The optical fiber unit 2 of the present application includes an optical fiber unit core layer 21 and an optical fiber unit cladding layer 22 .

[0061] In some specific embodiments, the optical fiber unit 2 uses any one of single-mode optical fiber, multi-mode optical fiber and D-type optical fiber, and the material of the optical fiber unit 2 uses any one of compliant optical fiber, plastic optical fiber and glass optical fiber.

[0062] Types of the optical fiber unit 2 include but are not limited to the above-mentioned single-mode optical fiber, multi-mode optical fiber and D-type optical fiber, and materials of the optical fiber unit 2 include but are not limited to the above-mentioned materials.

[0063] The optical fiber unit 2 of the present application can efficiently guide the optical signal output by the excitation light source into the photon lead 5 and the grating coupler 3 , and transmit back the sensing signal modulated by the waveguide layer of the sensing unit 4 .

[0064] In some specific embodiments, an integrated sensor based on a photonic lead further includes a grating coupler 3, which is arranged at both ends of the waveguide layer 41 of the sensing unit 4. The grating coupler 3 is connected to the optical fiber unit 2 through a photonic lead 5. The grating coupler 3 is used for input of optical signals and waveguide output.

[0065] Specifically, the present application adopts dual-photon printing technology to directly connect the photon lead 5 with the optical fiber unit 2 and the grating coupler 3. The optical fiber unit 2 is connected to one end of the photon lead 5, and the other end of the photon lead 5 is connected to the grating coupler 3 to realize the input and output of the optical signal and reduce the loss and instability in the traditional packaging method.

[0066] The material of the photon lead 5 is any one or more combinations of ultraviolet curing photosensitive polymer and organic-inorganic hybrid material.

[0067] The refractive index of the photon lead 5 is between that of the waveguide material of the optical fiber unit 2 and the grating coupler 3 , forming a graded refractive index transition structure. In addition, the thermal expansion coefficient of the photon lead 5 matches that of the material of the wafer 1 .

[0068] Specifically, the photon lead 5 adopts a three-dimensional tapered transition structure, the cross-sectional diameter of the input end of the photon lead 5 matches the cross-sectional diameter of the fiber core of the optical fiber unit 2, and the cross-sectional diameter of the output end of the photon lead 5 matches the waveguide width of the grating coupler 3.

[0069] Reference Figure 1 As shown, in this embodiment, the propagation path of the optical signal is: the excitation light source outputs the optical signal, the optical signal is input into the optical fiber unit 2 at one end, input into the photon lead 5 at one end via the optical fiber unit 2, input into the grating coupler 3 located at the same end via the photon lead 5, and transmitted through the waveguide layer 41 of the sensing unit 4, wherein the optical signal of a specific wavelength is coupled into the waveguide layer 41 of the sensing unit 4, and the remaining optical signal is transmitted to the grating coupler 3 at the other end, and is transmitted to the optical fiber unit 2 at the other end via the photon lead 5 at the other end.

[0070] Specifically, the optical fiber unit 2 , the photon lead 5 and the grating coupler 3 are respectively provided at both ends of the waveguide layer 41 of the sensing unit 4 .

[0071] In some specific embodiments, an integrated sensor based on photonic leads may further include a protective layer, which is disposed on the surface of the integrated sensor based on photonic leads. The protective layer is used to protect the integrated sensor based on photonic leads and reduce environmental interference with device performance.

[0072] Specifically, a protective layer may be selectively provided at the optical fiber unit 2 and the integrated device according to the application scenario of the sensor.

[0073] The protective layer may be made of, but not limited to, inorganic-flexible composite materials.

[0074] For example, the protective layer can be made of SiO2+PDMS, and the light reflection is reduced by adjusting the gradient refractive index. The outer layer of the protective layer is covered with a hydrophobic and anti-reflective coating, and is prepared by plasma enhanced chemical vapor deposition and spin coating process. The protective layer can have both mechanical protection and environmental stability.

[0075] The present application provides an integrated sensor based on photon leads, which can monitor temperature, humidity and biological signals by changing the type of sensing unit 4, and can control the size of the sensor by adjusting the sensor packaging position.

[0076] The preferred features of the above embodiments can be used alone in any embodiment, or in any combination without conflict. In addition, parts not described in detail in the embodiments can be implemented using existing technologies.

[0077] The following further illustrates the present application in conjunction with specific application examples / comparative examples to facilitate a better understanding of the above technical solutions of the present application. It should be understood that the following are merely partial examples and are not intended to limit the present application.

[0078] Reference Figure 1 As shown, Figure 1 The integrated sensor based on photonic leads is also represented as an integrated optical temperature sensor based on photonic leads, which uses a microring resonator as the waveguide layer 41 of the sensing unit 4, and uses a temperature detection unit as the functional layer of the sensing unit 4, and uses a photonic lead 5 to connect the sensing unit 4 and the optical fiber unit 2.

[0079] An integrated optical temperature sensor based on photon leads comprises: a wafer 1, an optical fiber unit 2, a grating coupler 3, a sensing unit 4, and a photon lead 5.

[0080] For the integrated optical temperature sensor based on photonic leads, the input path of the optical signal is:

[0081] The optical fiber unit 2 at one end guides the optical signal output by the excitation light source into the photon lead 5 at one end, and the optical signal is transmitted to the grating coupler 3 at one end through the photon lead 5 constructed using the two-photon printing technology.

[0082] Specifically, the grating coupler 3 may be made of silicon nitride or silicon-based materials. The grating coupler 3 is used to optimize the grating period and coupling angle of the optical signal to achieve efficient coupling of the optical signal.

[0083] Sensor signal excitation and modulation:

[0084] The optical signal is transmitted in the low-loss waveguide layer 41 and input into the sensing unit 4 through the directional grating coupler 3. The waveguide layer 41 of the sensing unit 4 takes a microring resonant cavity as an example. The distance between the microring resonant cavity and the coupled waveguide layer 41 is set to 100-300nm, and the resonant mode is excited by the critical accidental condition.

[0085] When the external ambient temperature changes, the effective refractive index of the microring resonator changes and the resonant wavelength shifts.

[0086] Signal output and detection:

[0087] The modulated signal of the sensing unit 4 is extracted by the grating coupler 3 at the other end, and is transmitted back to the optical fiber unit 2 at the other end through the photon lead 5 at the other end, and is finally transmitted to the external detection system.

[0088] Functional materials such as graphene oxide coating are provided in the waveguide layer 41 of the sensing unit 4 to enhance the absorption characteristics of signals of specific wavelengths. The signal-to-noise ratio is improved by combining the phase-locked amplification technology. The entire optical path is encapsulated under a silicon dioxide protective layer to reduce the phase noise caused by environmental disturbances.

[0089] Figure 2 The figure is a schematic diagram of the overall structure of an integrated optical humidity sensor based on photon leads according to an exemplary embodiment.

[0090] Reference Figure 2 In one embodiment of the present application, an integrated optical humidity sensor based on a photon lead is provided, wherein the functional layer of the sensing unit 4 adopts polyvinyl alcohol as a humidity-sensitive medium, and the waveguide layer 41 of the sensing unit 4 adopts an Euler-type microring resonant cavity, and a photon lead 5 is used to connect the sensing unit 4 and the optical fiber unit 2.

[0091] An integrated optical humidity sensor based on photon leads comprises: a wafer 1, an optical fiber unit 2, a sensing unit 4, and a photon lead 5.

[0092] For the integrated optical humidity sensor based on photon leads, the optical fiber unit 2 at one end introduces the optical signal output by the excitation light source into the photon lead 5 at one end. The photon lead 5 at one end transmits the optical signal to the grating coupler 3 at one end and transmits it to the Euler microring resonator of the sensing unit 4. After the polyvinyl alcohol (PVA) humidity-sensitive medium coated on the surface of the Euler microring resonator adsorbs environmental water molecules, its refractive index changes with humidity and the resonant wavelength shifts. The remaining optical signal is input to the grating coupler 3 at the other end and transmitted to the optical fiber unit 2 at the other end through the photon lead 5 at the other end, and output to the externally connected detector to capture the wavelength offset in real time. The externally connected signal processing unit converts the wavelength offset into a humidity value and outputs it.

[0093] Among them, the photon lead 5 adopts a flexible coupling design to ensure low-loss transmission, while buffering external mechanical interference to achieve fast and stable humidity detection.

[0094] The present application provides an integrated sensor based on photonic leads, which realizes the integration of micro sensors on optical fibers, solving the inherent defects of large size, high loss and unstable structure when vertical coupling or end-face coupling is used in the prior art. It has the advantages of high integration, small size and low loss. In addition, this technology is compatible with the development of various types of integrated sensors such as temperature, humidity and pressure, greatly expanding the application scenarios of existing micro-nano optics.

[0095] Figure 3 The figure is a flow chart of a method for preparing an integrated sensor based on photonic leads according to an exemplary embodiment.

[0096] Reference Figure 3 As shown, another embodiment of the present application provides a method for preparing an integrated sensor based on photonic leads, including S11 to S14.

[0097] S11, spin-coating a photoresist on a preset wafer, and performing grating patterning on the wafer on which the photoresist is spun, to determine a patterned photoresist.

[0098] Specifically, the wafer on which the photoresist is spin-coated is subjected to grating patterning, and can be developed by electron beam direct writing lithography or ultraviolet lithography to form a patterned photoresist.

[0099] S12, using a plasma dry etching process to etch the non-photoresist area on the wafer to generate a sensing unit and a grating coupler.

[0100] Exemplarily, a plasma dry etching process is used to etch the area on the wafer that is not protected by the photoresist, that is, the photoresist-free area, into an optical resonant microring waveguide, that is, a sensing unit, and a grating coupler conversion waveguide, that is, a grating coupler.

[0101] In the present application, the optical fiber unit adopts a preset optical fiber unit, that is, a preset optical fiber.

[0102] S13, using femtosecond laser scanning of photosensitive polymer to generate photonic leads connecting the preset fiber unit and grating coupler.

[0103] Specifically, the waveguide structure parameters are optimized based on optical path simulation modeling to ensure high-precision fitting and low-loss characteristics of the optical transmission path. Femtosecond laser scanning is used to form a photosensitive polymer through two-photon polymerization to achieve mode field matching coupling between the preset optical fiber unit and the sensing unit.

[0104] S14, depositing a protective layer on the surface of the wafer, the sensing unit, the grating coupler, the preset optical fiber unit, and the photonic lead to determine an integrated sensor based on the photonic lead.

[0105] Specifically, the protective layer is deposited under high temperature conditions.

[0106] The above-mentioned embodiments of the present application, based on the connection method of the photonic lead and combined with the protective layer, significantly reduce the mode field mismatch loss and greatly improve the stability under extreme temperature, humidity and mechanical vibration, ensuring the long-term reliable operation of the sensor; optimize the two-photon direct writing technology to achieve fast and high-precision photonic lead manufacturing, and are compatible with CMOS technology, support wafer-level integration, significantly reduce packaging costs and promote the large-scale application of miniaturized sensors.

[0107] In some possible embodiments, the material of the protection layer is any one or more combinations of silicon oxide, silicon nitride and polyimide.

[0108] In the above embodiments of the present application, providing a flexible composite protective layer can reduce sensor device loss and improve the quality factor.

[0109] The method for preparing an integrated sensor based on photon leads of the present application may further include S15 to S16.

[0110] S15, after the photolithography is completed, the unpolymerized resin is removed by development and the waveguide structure is dried and solidified.

[0111] S16, performing plasma activation treatment on the coupling interface between the photon lead and the optical fiber unit, and filling the interface with flexible epoxy resin.

[0112] Specifically, steps S15 to S16 are performed after the above-mentioned step S13.

[0113] In the above-mentioned embodiments of the present application, the surface activity of the coupling interface between the photon lead and the optical fiber unit is enhanced by plasma activation treatment, and the flexible epoxy resin is filled to optimize the interface refractive index and reduce the insertion loss.

[0114] Figure 4 The figure is a schematic diagram showing the preparation of an integrated optical temperature sensor based on photonic leads according to an exemplary embodiment.

[0115] Reference Figure 4 As shown, the first step represents the preparation and surface treatment of the optical fiber taper, in which an optical fiber is prepared on a wafer, the optical fiber end face is cleaned with hydrofluoric acid, the optical fiber cladding is removed at an appropriate position, and the optical fiber is cut to form an optical fiber unit.

[0116] The second step is chip preprocessing and alignment. An infrared alignment system is used to fix and bond the sensor unit to the top of the wafer with UV curing glue. The sensor unit is used to detect temperature.

[0117] The third step is to form a waveguide through two-photon printing to achieve mode field matching coupling between the optical fiber unit and the sensing unit to form a photonic lead.

[0118] In the above-mentioned embodiment of the present application, a photon lead connecting the optical fiber unit and the sensor unit is formed by two-photon printing, thereby achieving mode field matching coupling between the optical fiber unit and the sensor unit and reducing mode field mismatch loss.

[0119] Figure 5 The figure is a schematic diagram showing the preparation of a sensing unit according to an exemplary embodiment.

[0120] Reference Figure 5 As shown, silicon SOI on an insulating substrate is used as a micro-ring resonator of a sensing unit of a wafer, including S1 to S6.

[0121] S1, substrate pretreatment: Use a clean wafer as the base material.

[0122] Specifically, the materials of the wafer include silicon dioxide 7 and silicon 8 .

[0123] S2, grating patterning: spin-coating a photoresist 6 on the wafer and developing it using electron beam lithography to form a primary patterned mask.

[0124] S3, shallow silicon etching: plasma deep silicon etching is used to selectively etch the silicon layer at a depth of 70 nm in the unmasked area to construct a coupled grating structure.

[0125] S4, waveguide layer patterning: re-spin-coating the photoresist 6 on the wafer, and performing secondary development using electron beam lithography to form a secondary patterned mask.

[0126] S5, deep silicon etching: Use plasma deep silicon etching to etch the silicon layer to a depth of 220nm in the unmasked area to define the main structure of the sensor.

[0127] S6, surface passivation and packaging: deposit silicon oxide on the surface of the sensor device as a passivation protection layer.

[0128] Specifically, a chemical vapor deposition (CVD) or physical vapor deposition (PVD) process is used to form a uniform silicon oxide film on the surface of the sensor device.

[0129] The present application provides a method for preparing an integrated sensor based on photonic leads. Through the flexible combination of materials and structures, it is compatible with single-mode and multi-mode optical fibers, a variety of waveguide materials and functional coatings. It is suitable for diverse scenarios such as biological implant monitoring, industrial equipment status perception and autonomous driving lidar, providing an all-optical interconnection foundation for intelligent sensor networks.

[0130] The above describes specific embodiments of the present disclosure. It should be understood that the present disclosure is not limited to the specific embodiments described above, and those skilled in the art may make various modifications or variations within the scope of the claims, which do not affect the essence of the present disclosure. The above preferred features may be used in any combination as long as they do not conflict with each other.

Claims

1. An integrated sensor based on photon leads, characterized in that: include: A wafer, a sensing unit, an optical fiber unit, and a photon lead. The sensing unit is arranged on top of the wafer, and the sensing unit is also bonded to the optical fiber unit. The optical fiber unit is connected to the sensing unit through the photon lead. The wafer is used to support the sensing unit. The sensing unit is used to modulate the optical signal. The optical fiber unit is used to input the optical signal output by the excitation light source into the photon lead and receive the modulated signal of the sensing unit transmitted back. The photon lead is used for input and output of the optical signal.

2. The integrated sensor based on photonic leads according to claim 1, characterized in that The invention also includes a protective layer, which is arranged on the surface of the integrated sensor based on the photon lead, and is used to protect the integrated sensor based on the photon lead.

3. The integrated sensor based on photonic leads according to claim 1, characterized in that The sensing unit includes a waveguide layer and a functional layer. The waveguide layer adopts an optical resonant cavity structure, and the optical resonant cavity structure adopts any one or more combinations of a microring resonant cavity, a nanobeam resonant cavity, a multi-ring resonator array, a Fabry-Perot resonant cavity, a whispering gallery mode resonant cavity, or a photonic crystal resonant cavity. The material of the waveguide layer adopts any one or more combinations of silicon, silicon nitride, lithium niobate thin film, indium phosphide, or gallium arsenide. The waveguide layer is used as an optical transmission channel, and the functional layer is used to perform preset functional detection on the detection target.

4. The integrated sensor based on photonic leads according to claim 1, characterized in that The optical fiber unit is made of any one of single-mode optical fiber, multi-mode optical fiber and D-type optical fiber, and the material of the optical fiber unit is made of any one of adaptive optical fiber, plastic optical fiber and glass optical fiber.

5. The integrated sensor based on photonic leads according to claim 1, characterized in that: It also includes a grating coupler, which is arranged at both ends of the waveguide layer of the sensing unit. The grating coupler is connected to the optical fiber unit through the photon lead, and is used for input of optical signals and waveguide output.

6. The integrated sensor based on photonic leads according to claim 5, characterized in that: The photon lead adopts a three-dimensional tapered transition structure, the cross-sectional diameter of the input end of the photon lead matches the cross-sectional diameter of the core of the optical fiber unit, the cross-sectional diameter of the output end of the photon lead matches the waveguide width of the grating coupler, and the material of the photon lead adopts any one or more combinations of ultraviolet-curable photosensitive polymers and organic-inorganic hybrid materials.

7. The integrated sensor based on photonic leads according to claim 1, characterized in that: The material of the wafer is any one or more combinations of silicon-on-insulator wafer, silicon wafer, sapphire and quartz. The wafer is used as a substrate of the integrated sensor based on photon leads.

8. The integrated sensor based on photonic leads according to claim 2, characterized in that: The protective layer is made of an inorganic-flexible composite material.

9. A method for preparing an integrated sensor based on photon leads, characterized in that: include: Spin-coating a photoresist on a predetermined wafer, and performing grating patterning on the wafer on which the photoresist is spun, to determine the patterned photoresist; Etching the non-photoresist area on the wafer using a plasma dry etching process to generate a sensing unit and a grating coupler; Using a femtosecond laser to scan a photosensitive polymer to generate a photonic lead connecting a preset optical fiber unit and the grating coupler; A protective layer is deposited on the surfaces of the wafer, the sensing unit, the grating coupler, the preset optical fiber unit, and the photon lead to determine an integrated sensor based on the photon lead.

10. The method according to claim 9, characterized in that The material of the protective layer is any one or more combinations of silicon oxide, silicon nitride and polyimide.

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